Answer:Spectroscopy helps astronomers to determine the composition, temperature, density, and motion of an object.
Infrared spectroscopy helps to identify the atoms and molecules in the object.
The red shift or blue shift (Doppler Effect) in a spectral line tells how fast the object is receding from Earth or coming toward it.
The Doppler shift enables astronomers to discover extrasolar planets.
As a planet orbits its star, the star is alternately moving away from or toward us.
Astronomers can use the Doppler shifts to calculate the speed of the star and the mass of the planet that is tugging on it.
Explanation:
The correct answer is option B, hydrogen.
The majority of the atmospheric gases are found in the sea water solution. In supplementation to oxygen and nitrogen, the most profusely found gas in the atmosphere, that is, carbon dioxide is found in the ample concentrations in the ocean waters.
However, hydrogen is not present, and if found it is found in minute concentration. Of the gases, nitrogen is the most abundant gas found in seawater, while oxygen is the second most abundant, and carbon dioxide is the most soluble gas, and one of the various constituents, which influences the pH balance of the ocean.
<span>The answer to 10 is A as liquids expand with an increase in temperature. 12. Not able to answer. The answer to 17 is A as a the two different metals expand and contract at different rates when heated and cooled.</span>
